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Squares Trick Worksheet

Speed calculation lesson 10: Squares next to a ten · Set 818 · 40 questions
TalentJR

The fast method (Step from a neighbour): Find the round neighbour and square it: 70² = 7 × 7 = 49, then two 0s → 4900. Ends in 1 (one more)? Add the round number and the number: 4900 + 70 + 71. Ends in 9 (one less)? Take them away: 69² = 4900 − 70 − 69 = 4761.

NameDateTime takenScore ___ / 40
  1. 1.31² =
  2. 2.81² =
  3. 3.19² =
  4. 4.39² =
  5. 5.19² =
  6. 6.79² =
  7. 7.69² =
  8. 8.91² =
  9. 9.81² =
  10. 10.71² =
  11. 11.71² =
  12. 12.29² =
  13. 13.51² =
  14. 14.69² =
  15. 15.89² =
  16. 16.21² =
  17. 17.51² =
  18. 18.79² =
  19. 19.61² =
  20. 20.79² =
  21. 21.71² =
  22. 22.59² =
  23. 23.89² =
  24. 24.29² =
  25. 25.89² =
  26. 26.69² =
  27. 27.41² =
  28. 28.89² =
  29. 29.89² =
  30. 30.59² =
  31. 31.81² =
  32. 32.51² =
  33. 33.31² =
  34. 34.79² =
  35. 35.91² =
  36. 36.41² =
  37. 37.59² =
  38. 38.51² =
  39. 39.61² =
  40. 40.89² =

Answer key

  1. 961
  2. 6561
  3. 361
  4. 1521
  5. 361
  6. 6241
  7. 4761
  8. 8281
  9. 6561
  10. 5041
  11. 5041
  12. 841
  13. 2601
  14. 4761
  15. 7921
  16. 441
  17. 2601
  18. 6241
  19. 3721
  20. 6241
  21. 5041
  22. 3481
  23. 7921
  24. 841
  25. 7921
  26. 4761
  27. 1681
  28. 7921
  29. 7921
  30. 3481
  31. 6561
  32. 2601
  33. 961
  34. 6241
  35. 8281
  36. 1681
  37. 3481
  38. 2601
  39. 3721
  40. 7921

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